ICD-10 Code L91 – Hypertrophic Disorders of Skin (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L91 – Hypertrophic disorders of skin
What it is
L91 identifies hypertrophic disorders of skin, a group of conditions marked by excess skin thickening or overgrowth. Use it when the record documents a hypertrophic skin change rather than a specific scar or keloid diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Typical findings include raised, thickened, or overgrown skin lesions that may follow injury, inflammation, or chronic irritation.
When to use this code
Use L91 when the provider documents a hypertrophic disorder of the skin and does not name a more specific codeable condition. It may apply to diffuse skin thickening or localized hypertrophic change. Check documentation for the exact anatomic site and cause.
Do not use for
Do not use this code for keloids when a more specific code is documented. Also avoid it if the note describes another skin disorder, such as a scar condition or a different lesion type.
Coding tip
Code the most specific documented skin disorder first; if the record only says “hypertrophic skin changes,” L91 is appropriate.